Filtering the data

Hi Team,

Can any one please help to get my requirement, it is very urgent.

I have data like below

I should define the filter with the values A, B, C and D. X records should combined with any one of the values in the product.

And Product is multiple selection.

If i select A , then A+X values should show,

If i select B, then B+X should display.

when i do multiple selction then, X values should go any one of the prod.

I have tried defining like below.

if [Prod]='A' or [Prod]='X' then "A"

ELSEIF [Prod]='B' or [Prod]='X' then "B"

ELSEIF [Prod]='C' or [Prod]='X' then "C"

ELSEIF [Prod]='D' or [Prod]='X' then "D"

END

But x vlues are going only to A prod.

when i select any other x values are not coming to other prods.

Can any one help me how to resolve this issue.